The present invention relates to machine collets, and more particularly to a sealing collet for use with tools having a through-hole for the induction of cooling fluid through the tool.
A variety of conventional drills and tools are commercially available having holes or passages defined therethrough to enable the induction of coolant to the cutting edge or working surfaces of the drill or tool. Coolant is a cutting fluid known to reduce the frictional forces acting on the drill. However, in order for a cutting fluid to function effectively, two requirements must be met. First, the fluid must have the thermal capability of removing heat generated by the tool and, secondly, the fluid must reach the cutting area or working surfaces of the tool. In order to use this conventional type of through-hole drill the collet holding the drill must be sealed to allow the coolant to flow to the cutting edge of the drill at a relatively high pressure. If the collet is not adequately sealed, the coolant will leak from around the tool holder cone and the tool holder nut and will not reach the cutting edge with adequate pressure and flow.
Conventional sealing collets are commercially available, such as the ER-COOLIT.TM. Collet manufactured by Engineers Tool Manufacturing Company, Limited, of Israel and sold through GTE Valenite Corporation of Troy, Mich. Another example of conventional sealing collets are the Sealing Collets sold by Rego-Fix Tool Corporation of Indianapolis, Ind. The conventional sealing collets, such as the type mentioned, relate to the commonly known split steel type collets.
Applicant, however, has determined that the conventional sealing collets are generally inadequate since they seal only at relatively low pressures and at nominal clamping diameters only. A reason for this inadequacy may be that the conventional split steel collets are made into sealing collets by adding a sealing media between the steel segments. This media is very expensive and does not hold very well to the split steel segments.
The Jacobs.RTM. Chuck Manufacturing Company manufactures and markets a well known Rubber-Flex.RTM. Collet of the type having a plurality of individual gripping members held in position and equally spaced about a common axis. The spaces between the gripping members is filled with an adherent resilient material, such as rubber or rubber composition. The gripping members have perforations therethrough so that the resilient material not only fills the space between the gripping members but also passes through the perforations forming a plurality of longitudinally spaced continuous angular rings which hold the gripping members in a desired relative position. Applicant has, with the present invention, configured a Rubber-Flex.RTM. type collet as a sealing collet which has proven to be far superior to conventional sealing collets.